New functional dissociations between prefrontal and parietal cortex during task switching: A combined fMRI and TMS...

Area of Science:

• Cognitive Neuroscience
• Neuropsychology

Background:

• Task-switching relies on frontoparietal networks for preparatory control.
• Previous studies offer conflicting evidence regarding the specific roles of frontal and parietal cortices in switch-specific preparation.

Purpose of the Study:

• To clarify the distinct roles of prefrontal and parietal areas in preparatory cognitive control during task-switching.
• To investigate the involvement of the right inferior frontal gyrus (IFG) and right intraparietal sulcus (IPS) in switch and repeat trials.

Main Methods:

• Functional magnetic resonance imaging (fMRI) identified brain regions activated during task-switching cue events.
• Transcranial magnetic stimulation (TMS) was applied to the right IFG and right IPS to assess causal roles.

Main Results:

• TMS over the right IFG impaired performance in both switch and repeat trials, suggesting a general role.
• TMS over the right IPS selectively disrupted performance in switch trials, indicating a switch-specific role.

Conclusions:

• The findings support a multi-component model of executive control.
• The IFG is implicated in general, switch-unspecific processes like goal retrieval.
• The IPS is crucial for switch-specific preparation, including stimulus-response mapping activation.